Description:

RK4 is an Excel^® add-in to produce a spreadsheet that implements a 4^th order Runge-Kutta method for the solution of small to medium-size initial value simulation studies. It is compatible with Excel^® 97 to Excel^® 2003.

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Rationale:

Excel spreadsheets are familiar to several users.This means faster learning curves plus wider/efficient distribution of simulation templates.

 

The resulting spreadsheets can be processed/analyzed further using other Excel^® functions and add-ins such as SOLVER^®.

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Simulation Templates:

These are spreadsheets which contain spreadsheet formulas, scrollbars and plots ready for simulation studies of a particular system.

Even though they are produced by RK4, the simulation templates are spreadsheets which can be distributed for use with or without RK4.

An example of a simulation template is PhaseDiag.xls (shown in Figure 1 below) and which can be downloaded by clicking here.

Some highlights of RK4-generated simulation templates:

• Scrollbars allow for easier changes in either initial conditions or parameters.  The subset of initial conditions or parameters that will be attached with scrollbars are determined during implementation of RK4.

 
• Arrows can be attached to trajectories (see Plot 2 in Figure 1). This is specially-useful for phase plane analysis. For additional arrow attachments of new plots, the RK4 add-in is needed.

 

Figure 1. A snapshot of PhaseDiag.xls.

The RK4 Add-In:

Download:  RK4_v3_0.zip (click here) [ or for RK4 v2_0.zip ( click here )]

Manual/Tutorial: RK4_v3.0 manual.pdf

( Click here to view/download pdf file. Also available in zip file above.)
 

Compatiblity : Excel^® 97 and later versions
 

Some highlights:

• VBA user forms for generating simulation templates (see Figure 2).

These forms also consist of some error-checking routines.



                       Figure 2. RK4 user form.
 
 

• VBA user-forms for generating various plots, including the ability to attach arrows to trajectories.

 

 
 
 
 
 
 
 



                       Figure 3. Plotting user form.
 
 

• Ability to open and save model files. Model files are text files which can be generated using the RK4 add-in, WORDPAD^®, NOTEPAD^® or any available text editor.